Existing electronic lock systems are used to control access to various areas within a facility. Some systems employ wireless locks that communicate with an interface device, also known as a panel interface module, sufficiently proximate to the electronic locks to enable radio communication. The interface device is configured to monitor and control the state of a predetermined number of electronic locks, such that multiple interfaced devices can be required in a facility of a large size, since one interface device can be insufficient to monitor and control all of the electronic locks in the facility. Consequently, a number of interface devices are hardwired to a central controller, also known as an access control panel, and are connected to the computer system of the facility. In some facilities, more than one access control panel can be required. The computer system provides updates to the electronic locks through this radio communication network. However, the hardwired connection of the interfaces devices with the access control device can be expensive in large facilities, and creates concerns that the hardwiring is redundant with the existing wiring of the various area networks of the facility.
Some existing systems, when used inside a building or other structure, are susceptible to multi-path interference from door and hall passages, individuals, and architectural construction which limit the effective range of communication between the interface device and the electronic lock, each of which includes a receiver and a transceiver. Because of the multi-path interference, wireless locks sometimes have intermittent reception in indoor environments that makes the working range unpredictable. When the interface device and the electronic lock are in clear sight of each other, the electronic communication between the two can pass directly from one antenna to the other.
When there is no clear line-of-sight between the interface device and the electronic lock, the wireless electronic signal can reach the receiver of the electronic lock over multiple paths. The electronic signals traveling along multiple paths will be out of phase with other received signals and cause the multi-path distortion. In a typical office or industrial setting, multi-path distortion can be caused by the location of locks relative to interface device, and can even change dynamically as individuals move about the facility and doors are opened and closed. A receiver at the electronic lock attempts to decode the original signal from the distorted signal. If the distortion is too high, the receiver can fail to decode the transmitted signal and a communication error results. Because of this, the interface device must be relocated, usually closer to the electronic lock. In some cases, the number of interface devices must be increased to accommodate the facility, even though the interface device is not being fully utilized. What is needed, therefore, is an electronic door lock system which reduces signal distortion resulting from the configuration of the facility and the location of the electronic locks.